Facies Architecture and Production Characteristics of Strandplain Reservoirs in the Frio Formation, Texas

RI0146. Facies Architecture and Production Characteristics of Strandplain Reservoirs in the Frio Formation, Texas, by Noel Tyler and W. A. Ambrose. 42 p., 29 figs., 1 table, 1985. ISSN: 0082335X: Print.


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ABSTRACT

Many modern shore zones comprise a continuum of depositional environments that

encompass both strandplain and barrier-island systems. Strandplains are further subdivided

into two classes: sand-rich beach-ridge plains and mud-rich chenier plains. Tertiary shorezone

systems of the Texas Gulf Coast Basin contain a significant proportion of the Texas oil

resource in clastic reservoirs. These reservoirs display better-than-average oil recovery

efficiencies. This report describes the production attributes of three Frio strandplain

reservoirs---the Cayce, the Cornelius, and the Carlson---in the North Markham-North Bay

City field, Matagorda County, Texas.

Hydrocarbons in the North Markham-North Bay City field were trapped in a simple

rollover anticline. Oil is produced from stacked strandplain sandstones in this multiple reservoir

field. Composite sandstones of beach-ridge plain/distributary/delta-front origin

constitute the Cayce oil reservoir. Internal heterogeneity results in considerable fluid-flow

anisotropy, as displayed by sequential water-cut maps and oil production maps. Water influx

in the strandplain deposits follows broad fronts, whereas water invasion in channel deposits is

more restricted and erratic. The Cornelius reservoir was deposited in a system intermediate

between sand-rich beach plains and mud-rich chenier plains. Sandy beach ridges, separated

by muddy swales, compose the productive framework of this class of strandplain reservoir

and furthermore act as conduits for early water influx. Sandstones, possibly of washover

origin, in the intervening swales produce oil but are more rapidly drained than are beach-ridge

sandstones. The Carlson reservoir produces from transgressed strandplain deposits. Oil is

contained in upward-fining transgressive sandstones that rest on thicker but oil-barren

progradational facies. Facies analysis indicates that the Carlson had a complex and episodic

depositional history, yet water-influx maps and oil production maps suggest isotropic fluid

behavior. Modern sand-rich transgressive shore-zone deposits are characteristically

sheetlike, as is the transgressive component of the Carlson reservoir. This distinctive

morphology appears to have fostered reservoir productivity.

Oil recovery from the North Markham-North Bay City reservoirs follows a predictable

trend. Recovery efficiency is highest from the transgressive sheet sands of the Carlson, which

is the shallowest of the major oil reservoirs; intermediate from the composite Cayce; and

lowest from the depositionally complex and mud-rich Cornelius, which overlies the Cayce.

Reservoir efficiency of the strandplain sandstones in the North Markham-North Bay City

field exceeds that of barrier and back-barrier deposits productive elsewhere in the Frio

Formation of the central Texas Gulf Coast.

Keywords: Texas Gulf Coast, Matagorda County, Frio Formation, North Markham-North Bay City oil field, strandplain reservoirs, reservoir architecture, oil production


CONTENTS
ABSTRACT

INTRODUCTION

Strandplain depositional systems

Beach-ridge plains

Chenier plains

Oil-bearing strandplain systems of the Texas Gulf Coast Basin

NORTH MARKHAM-NORTH BAY CITY FIELD

Oil production from the North Markham- North Bay City field

Facies influence on reservoir continuity

CAYCE RESERVOIR: A COMPOSITE PROGRADATIONAL STRANDPLAIN/FLUVIODELTAIC COMPLEX

Depositional environment

Thickness trends and sandstone distribution

Areal distribution of component facies

Interpretation of depositional environments

Architecture and dimensions of component facies

Areal stratification trends

Reservoir continuity and hydrocarbon distribution

Reservoir drainage characteristics

Water-influx trends

Reservoir productivity

CORNELIUS RESERVOIR: A PROGRADED MUD-RICH STRANDPLAIN COMPLEX

Depositional environment

Sandstone distribution

Areal distribution of component facies

Interpretation of depositional environments

Reservoir continuity and hydrocarbon distribution

Reservoir drainage characteristics

Water-influx trends

Reservoir productivity

CARLSON RESERVOIR: A TRANSGRESSED BEACH-RIDGE PLAIN

Depositional environment

Sandstone distribution

Areal distribution of component facies

Interpretation of depositional environments

Reservoir continuity

Reservoir drainage trends

CONCLUSIONS

Reservoir models

Oil recovery and fluid injection

ACKNOWLEDGMENTS

REFERENCES

 

Figures

1. Schematic models illustrating the principal environments of deposition in (A) beach-ridge plain, (B) chenier plain, and (C} barrier-island systems

2. Physiography of a modem beach-ridge strandplain, Nayarit coastal plain, Mexico, and a cross section illustrating the tabularity of prograding beach-ridge deposits

3. Physiography of a modem chenier plain, western Louisiana, and a cross section illustrating the shallow-based and irregular distribution of chenier plain beach ridges

4. Frio depositional systems and location of the North Markham- North Bay City field

5. Upper Frio stratigraphic dip cross section

6. Structure map of the North Markham-North Bay City field contoured on top of the Cayce sandstone

7. Generalized west-east section across the North Markham- North Bay City field

8. Percent-sandstone map, Cayce reservoir

9. Log-character and net-sandstone map, Cayce reservoir

10. Facies anatomy of the Cayce sandstone, adapted from vertical SP profiles

11. Exploded reservoir facies of the Cayce sandstone

12. Stratigraphic complexity (number of strata} map of the Cayce sandstone

13. Resistivity cross sections, east Cayce reservoir

14. Resistivity cross section, west Cayce reservoir

15. Sequential water-cut maps, east and west Cayce reservoirs

16. Reservoir productivity maps of the Cayce reservoir for periods 1942 through 1965 and 1966 through 1982

17. Net-sandstone map, Cornelius sandstone

18. Detailed net-sandstone map of the third Cornelius sandstone

19. Interpretive facies anatomy of the third Cornelius sandstone

20. Resistivity dip sections, Cornelius sandstone

21. Resistivity section aligned obliquely to the strike of the Cornelius sandstone

22. Sequential water-cut maps of the west Cornelius reservoir

23. Reservoir production maps, west Cornelius reservoir

24. Log-facies map of the Carlson sandstone

25. Resistivity cross section, Carlson reservoir

26. Water-cut and production maps of the Carlson reservoir

27. Continuity of a composite progradational beach-ridge strandplain transected by a fluvial-deltaic system modeled on the Cayce reservoir

28. Reservoir continuity models of a mud-rich beach-ridge plain complex

29. Reservoir continuity model of transgressed strandplain sandstones

 

Table

1. Geologic, fluid property, engineering, and production characteristics of the principal oil reservoirs of the North Markham-North Bay City field



Citation
Tyler, Noel, and Ambrose, W. A., 1985, Facies Architecture and Production Characteristics of Strandplain Reservoirs in the Frio Formation, Texas: The University of Texas at Austin, Bureau of Economic Geology, Report of Investigations No. 146, 42 p.